The effect of Ag addition on the glass-forming ability of Mg–Cu–Y metallic glass alloys

The effect of Ag substitution for Cu on the glass forming ability was studied in Mg65Cu25−xAgxY10 (x=0,5,10,15,20,25) alloys by using thermal analysis and X-ray diffractometry (XRD). With increasing x from 0–25, the glass transition temperature, Tg, of melt spun Mg65Cu25−x AgxY10 alloys increases slightly from 426 to 436 K, and the crystallization temperature, Tx, decreases from 494 to 459 K, resulting in a decrease in the supercooled liquid region. However, a partial substitution of Cu by Ag in Mg65Cu25Y10 promotes the glass formation. The maximum diameter for amorphous phase formation by injection casting increases from 4 mm in Mg65Cu25Y10 to 6 mm in Mg65Cu15Ag10Y10 alloy. Both amorphous Mg65Cu15Ag10Y10 alloys prepared by melt spinning and injection casting showed similar crystallization process during continuous heating in differential scanning calorimetry (DSC). The relationship between the critical diameter for the formation of an amorphous phase in injection casting and the parameters reflecting glass-forming ability was examined.